Semiconductor photodetector structure and the fabrication method thereof

A semiconductor photodetector structure, comprising:

• a substrate, comprising a first semiconductor material and comprising a deep trench, wherein the surface of the deep trench comprises a first type dopant region which comprises a first type dopant, and the first type dopant region is disposed on a bottom surface of the deep trench wherein an area of the first type dopant region is smaller than the bottom surface of the deep trench;
• a photodetecting element disposed in the deep trench, wherein the photodetecting element comprises a second semiconductor material, and a bottom area of the photodetecting element is smaller than the area of the first type dopant region, and the bottom area of the photodetecting element is substantially parallel to the bottom surface of the deep trench;
• and
• a semiconductor layer disposed on the photodetecting element, wherein the semiconductor layer comprises a second type dopant.